It relates more particularly to a seat slide rail comprising:                a first profile section, intended to be attached to said vehicle, extending along a longitudinal axis, said first profile section having a cross-section with a bottom and two side parts,        a second profile section, guided translationally relative to the first profile section and able to move relative to said first profile section along the longitudinal axis, said second profile section having a cross-section with a central part with a U-shape open toward the bottom of the first profile section, having a web and first and second side flanges,        a sensor attached to the second profile section.        
Such slide rails for motor vehicles seats are already known, for example from document US2009/051356, which presents a slide rail provided with a detection sensor for detecting the position of a locking plate.
However, such a system is not compatible with motorized slide rail systems. In addition, the sensor has a large footprint and is difficult to integrate into the environment of the slide rail.